Planetary gear systems are used to provide gear reduction in a machine driveline. Planetary gear assemblies receive input from a drive shaft, which is typically splined to a sun gear. The sun gear is used to drive a plurality of planet gears spaced about the sun gear. The planetary gears are supported by a carrier.
Each of the planet gears is in meshing engagement with a ring gear. The sun gear drives the planet gears resulting in the planet gears driving the ring gear. The output from the ring gear is used to drive a member such as a wheel, for example.
Typically, planetary gear assemblies use multiple thrust washers to accommodate thrust loading supplied by the sun gear to the planet gears. A pair of thrust washers is supported on each of the planet gears. A first thrust washer is supported on one side of the planet gear and a second thrust washer is supported on an opposite side of the planet gear. Thus, if a planetary gear assembly includes three (3) planet gears, a total of six (6) thrust washers are required.
The thrust washers act as wear surfaces, protecting the planet carrier from wear due to thrust loads and rotation of the planet gears. Each of these thrust washers is typically held in place by a tab or pin that engages the planet carrier to prevent the washer from rotating with respect to the planet gears. These tabs or pins can wear into the carrier causing damage. In some instances the tabs or pins can break-off, causing pieces to enter the gear mesh, which can result in considerable damage to the gear drive.
Thus, it is desirable to have a planetary gear system that eliminates the pins and tabs required to prevent thrust washers from rotation with respect to the planet gears. Also, it is desirable to reduce the number of thrust washer members required in the planetary gear assembly to reduce cost and assembly time. Reduction of parts and elimination of the tabs will significantly decrease maintenance costs.
The present invention is directed to overcoming one or more of the problems set forth above.